The beauty of acid etched glass

I have three cories in a 30 gallon tank. The only other fish in the tank right now are neons and otos, and the stocking density is light. Two of the cories act perfectly normal. One originally did, but within the last week or so has taken to swimming frantically up and down the glass. I’ve never seen a fish swim so frantically in my life. I’ve tested practically every water parameter known to man (Ammonia, nitrite, nitrate, phosphorus, iron, CO2, pH, gH, kH…), and they are all perfectly fine. The tank is heavily planted with live plans and DIY CO2, but the CO2 is supposedly in the low range (lower than it should be for the plants) and all the other fish are acting perfectly normal. The other cories are as laid back as can be, and I can see nothing physically wrong with this fish. Occassionally he calms down and stops pacing, but he seems to spend the majority of his time doing this. Any idea what’s going on?

15 Comments

Interestingly enough fish can not tell their reflection from another fish, my corys tend to try to get into the background thinking its open water, also if you notice yoru corys have two “nostrils” and will dart up to the top of the water and suspend their heads above the water, why? because tehy can breath air using a laberinth organ like guoramis or bettas.

StarbucksCoffeeon November 30th, -0001

he is looking for food

Sunburston November 30th, -0001

They will eat algae clinging to the sides, as well as gather oxygen bubbles that adhere there as well, also if they notice you feeding them they may be trying to get your attention for food, but they dont always need food when they do this, so don’t overfeed because you think your fish is begging.

Sarahon November 30th, -0001

I have seen this other corys too. I think he is looking for food. I have seen it also if there is a lot of water movement in the tank. I read an article that said they do this when there are ready to breed. read the fifth paragraph of this link.http://www.articlefishtalk.com/Article/B…

SecretCelebrityon November 30th, -0001

you need to give him more sunlight and keep feding him

RadioActiveon November 30th, -0001

The reason is because it wants to see waht is going on

Give points i need alot of ponts

BlindPoeton November 30th, -0001

lol i used to have a cory cat and a chinese sucker in my community tank with a few others…. they were hillarious. both of them did that, constantly….. first, one would chase the other, then the other way around, it was great. they lived long healty lives…… i wouln’t worry about it, he’s probably just playin.

good luck!!

Caton November 30th, -0001

all fish do this, it’s just a game they play i guess. My gold barbs, my betta, and my ram cichlid all do this, but my barbs go real fast to the top of the water, lift a bit of water from the surface and shoot back down, it’s not anything to be worried about. This fish is probably just more active than the others.

OpenRoadon November 30th, -0001

my gourami does this and it’s quite healthy. It’s probably just a particularly active fish. Don’t worry at all.

KittyInCollinderon November 30th, -0001

I’m serious man all fish do this. I have a 30 gallon tank lke you do and My tiger barbs don’t do anything BUT this. The whole day they follow their reflection on the glass. From the inside of a tank theres alot of reflection.

CookieMonsteron November 30th, -0001

Most likely it’s just attracted to it’s reflection. Changing the lighting may help.

LighteningBolton November 30th, -0001

hehe, It’s just the way that they swim/school when they are happy. I have a shoal of 3 also and their swimming behavior is what makes me love them so much.

I’m trying to order more, julii corys are pretty rare where I live.
They will swim a ton more like that when they have 6 or more in their shoal (group). Its just the way they travel. They will often replicate exactly their shoal mates’ movements. =D

leeon May 15th, 2012

One of my Cory’s swims to the top edge just like some one else stated,”getting air”. Feeding or not, generally searches the bottom for food.
Love the tetras…wish the lakefish would strike bait like these fish eat! (Oops, my fish are giving me an angry look,haha!)

Moon August 26th, 2015

I had the same thing going on with 1 out of 3 corys. Its would swim frantically against the glass. There are several things I did that have improved the behavior. I added a background and more plants( fake) to the tank. I also made a cave out of a concave driftwood. Most importantly I started feeding them a little extra bottom feeder shrimp pellets.

All three of my corys are swimming against the glass when I wake up in the morning. They are hungry and calm down after I feed them and they thoroughly search the whole bottom for crumbs. The one that used to frantically swim has done it much less.
I have even seen corys in a nicely planted tank at the pet store doing this. They don’t have their cory care dialed in… they’re missing a cave and perhaps not enough food.

Moon August 26th, 2015

I had the same thing going on with 1 out of 3 corys. Its would swim frantically against the glass. There are several things I did that have improved the behavior. I added a background as I had it see through before.and more plants( fake) to the tank. I also made a cave out of a concave driftwood. Most importantly I started feeding them a little more bottom feeder shrimp pellets. Don’t go too crazy though.

All three of my corys are swimming against the glass when I wake up in the morning. They are hungry and calm down after I feed them and they thoroughly search the whole bottom for crumbs. The one that used to frantically swim has done it much less. I think it also has to do with large open stretches of glass (again not enough plants in a particular part of that tank it always did this in).

I have even seen corys in a nicely planted tank at the pet store doing this. They don’t have their cory care dialed in… they’re missing a cave and perhaps not enough food or plants not in the right spots.

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ALES LOMBERGAR is one of the few artisans in Europe who still practice the ancient art of glass acid etching which flourished in the late 19th century. Decorations are applied with resin resists by hand and then exposed to acid baths, with no machinery used. More information here.